This invention relates to control panels and the like for entering data by hand into digital equipment such as a digital processor. In the past, these mechanisms have included a wide variety of switches such as pushbutton switches, alternate action switches, and thumbwheel switches. Generally, the type of switch that is used depends upon the function that it is to perform.
For example, a plurality of thumbwheel switches are frequently used in conjunction with a single pushbutton switch to enter data such as numbers, addresses or commands. This is achieved by first selecting the data to be entered via the thumbwheel switches and then depressing the single pushbutton. If the data can be sent to more than one place, then another thumbwheel switch is often used in conjunction with the above described combination to select the data's destination.
One problem however, with the above described data entry mechanism is that the thumbwheel switches are relatively unreliable. This is because they have moving parts which tend to wear, corrode, and otherwise make poor electrical contact with use. As a result the reliability of these switches is substantially less than other electronic components that they are typically used with, such as integrated circuit chips.
Another problem with the mechanical thumbwheel switches is that they are relatively expensive as compared to the price of the integrated circuit chips. For example, a typical thumbwheel switch may cost three times as much as a typical logic chip. Thus, systems which presently use a large number of thumbwheel switches could achieve a substantial price reduction if the thumbwheel switches could be replaced with the circuit chips.
Therefore, it is one object of the invention to provide an electronic circuit that can replace thumbwheel switches.
Another object of the invention is to provide a data entry and display system that utilizes no thumbwheel switches.